/*
* Copyright (C) 2005-2011 MaNGOS <http://getmangos.com/>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef _VMAPTOOLS_H
#define _VMAPTOOLS_H

#include <G3D/CollisionDetection.h>
#include <G3D/AABox.h>

#include "NodeValueAccess.h"

/**
The Class is mainly taken from G3D/AABSPTree.h but modified to be able to use our internal data structure.
This is an iterator that helps us analysing the BSP-Trees.
The collision detection is modified to return true, if we are inside an object.
*/

namespace VMAP
{
	template<class TValue>
	class IntersectionCallBack
	{
		public:
			TValue*      closestEntity;
			G3D::Vector3 hitLocation;
			G3D::Vector3 hitNormal;

			void operator()(const G3D::Ray & ray, const TValue* entity, bool pStopAtFirstHit, float & distance)
			{
				entity->intersect(ray, distance, pStopAtFirstHit, hitLocation, hitNormal);
			}
	};

	//==============================================================
	//==============================================================
	//==============================================================

	class MyCollisionDetection
	{
		private:
		public:

			static bool collisionLocationForMovingPointFixedAABox(
			    const G3D::Vector3   &  origin,
			    const G3D::Vector3   &  dir,
			    const G3D::AABox    &   box,
			    G3D::Vector3      &     location,
			    bool          &         Inside)
			{

				// Integer representation of a floating-point value.
#define IR(x)   (reinterpret_cast<G3D::uint32 const&>(x))

				Inside = true;
				const G3D::Vector3 & MinB = box.low();
				const G3D::Vector3 & MaxB = box.high();
				G3D::Vector3 MaxT(-1.0f, -1.0f, -1.0f);

				// Find candidate planes.
				for(int i = 0; i < 3; ++i)
				{
					if(origin[i] < MinB[i])
					{
						location[i] = MinB[i];
						Inside      = false;

						// Calculate T distances to candidate planes
						if(IR(dir[i]))
						{
							MaxT[i] = (MinB[i] - origin[i]) / dir[i];
						}
					}
					else if(origin[i] > MaxB[i])
					{
						location[i] = MaxB[i];
						Inside      = false;

						// Calculate T distances to candidate planes
						if(IR(dir[i]))
						{
							MaxT[i] = (MaxB[i] - origin[i]) / dir[i];
						}
					}
				}

				if(Inside)
				{
					// definite hit
					location = origin;
					return true;
				}

				// Get largest of the maxT's for final choice of intersection
				int WhichPlane = 0;
				if(MaxT[1] > MaxT[WhichPlane])
				{
					WhichPlane = 1;
				}

				if(MaxT[2] > MaxT[WhichPlane])
				{
					WhichPlane = 2;
				}

				// Check final candidate actually inside box
				if(IR(MaxT[WhichPlane]) & 0x80000000)
				{
					// Miss the box
					return false;
				}

				for(int i = 0; i < 3; ++i)
				{
					if(i != WhichPlane)
					{
						location[i] = origin[i] + MaxT[WhichPlane] * dir[i];
						if((location[i] < MinB[i]) ||
						        (location[i] > MaxB[i]))
						{
							// On this plane we're outside the box extents, so
							// we miss the box
							return false;
						}
					}
				}
				/*
				// Choose the normal to be the plane normal facing into the ray
				normal = G3D::Vector3::zero();
				normal[WhichPlane] = (dir[WhichPlane] > 0) ? -1.0 : 1.0;
				*/
				return true;

#undef IR
			}
	};
}
#endif
